... disease incidence is decreasing in China, Japan and Korea, and Thailand where it appears to be associated with widespread vaccination campaigns; in contrast it appears to be increasing in parts of ... mumps virus (8), HSV (7)and measles virus (4). The aetiology remained unknown in 37 children (39%). No cases of encephalitis caused by mumps virus, measles virus or rubella virus were found in the ... vaccine againstthese viruses was introduced. This was also noted by otherresearchers in Finland [8]. In a small prospective study of central nervous system(CNS) infections in Helsinki, Finland...